1. Field of the Invention
The present application is related to information handling systems, and more specifically, to information handling systems having modular hot-pluggable electronic nodes and redundant power supplies.
2. Description of the Related Art
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes, thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
Mission critical information handling systems such as computer servers and associated storage disk arrays require availability twenty-four hours a day, seven days a week (24/7), without having to be shut down for maintenance, upgrading, or expansion. With high availability in mind, these information handling systems are being designed with modular subsystems, or “nodes,” that may be installed and removed without turning system power off or shutting down operation thereof (hereinafter, “hot-pluggable” or “hot-plugging”). Early examples of hot-pluggable modules (nodes) are input-output cards, modems, network interface cards, disk storage units and the like. More recently, hot-pluggable processing modules such as multiple central processing units (CPUs) with or without associate cache, Redundant Array of Independent Disks (RAID) disk storage, random access memory (RAM), system expansion chassis and the like are being designed for upgrading and/or expanding the information handling systems without interrupting operation thereof. New operating systems are also being developed to take advantage of these more complex hot-pluggable nodes for information handling system upgrades, expansion and maintenance.
To realize the aforementioned benefit and potential of using hot-pluggable nodes in the information handling system, noise free power must be maintained during insertion and removal thereof. Hot-pluggable nodes such as Network Interface Cards (NICs), modems, I/O ports and the like, have limited power requirements and do not impose a large load change on the information handling system power supply. However, the newer hot-pluggable multi-processor nodes, memory nodes, disk array nodes and the like, require a great deal of power from the information handling system power supply. These high power demand hot-pluggable nodes can create switching transients on the common power bus when inserted or removed from the information handling system. The power bus is also connected to other on-line nodes, and these switching transients, if not suppressed or eliminated, may cause catastrophic glitches to other operating nodes that ultimately will cause system crashes.
Prior methods of controlling switching transients when a hot-pluggable node is inserted or removed are: ramping-up voltage gradually to the newly connected node, or breaking the ground connection before power is disconnected from the hot-pluggable node. Either of these methods worked when the node did not require a lot of power. However, the multi-processor, memory, disk array and the like nodes require orders of magnitude more current (power) than the previous less complex hot-pluggable nodes.
Therefore, a problem exists, and a solution is required for inserting or removing hot-pluggable nodes having large power requirements without creating switching transients that could disrupt operation of a mission critical, high availability information handling system. The present invention is a response to the need for accommodating hot-pluggable nodes having large power requirements without disrupting other operating nodes in the information handling system.